Technical Field
The present disclosure relates to a puncture device and a chemical liquid supplying device, and particularly suited for supply of insulin into a body, for example.
Background Art
A so-called syringe pump type chemical liquid supplying device has been proposed as a device for supplying chemical liquid (insulin). This type of chemical liquid supplying device is a portable device attached to the skin of a user during use, and supplies chemical liquid into the body of the user by using a plunger which pushes the chemical liquid out of an outer cylinder filled with the chemical liquid (for example, see JP 2010-501283 A).
The chemical liquid supplying device supplies chemical liquid via a puncture needle inserted into the body of the user. As a structure of this type of puncture needle, there has been proposed a puncture needle having a double structure of a metal inner needle and a plastic outer needle (for example, see JP 2002-58747 A).
According to this type of puncture needle having a double structure, the metal inner needle projected from the tip of the plastic outer needle is inserted into the body of the user. Then, the metal inner needle is removed from the plastic outer needle. In this condition, chemical liquid is supplied via the outer needle as the only needle indwelled inside the body of the user.
According to the conventional puncture needle having a double structure, the outer needle functions as an indwelled needle to be indwelled within the body of the user.
When the diameter of the indwelled needle becomes smaller, the pain given to the user may decrease. However, according to the conventional puncture needle which inserts the metal inner needle into the outer needle functioning as the indwelled needle, the inside diameter of the outer needle functioning as the indwelled needle needs to be larger than the outside diameter of the metal inner needle. In this case, reduction of the diameter of the indwelled needle is difficult.